late period..please help asap!!

okay so the last time I got my period was on April 7th and I'm guessing it ended on the 12th. On April 10th I had a sexual encounter with my boyfriend. I have him a handjob and there was some pre cum and I'm worried it may have gotten on his fingers ((he was rubbing around my area as I gave him a handjob)) or on my fingers as well. I did have in a tampon while this all was happening but my period is now 10 days late according to this app. I'm concerned that I might be pregnant..a week or so after this all happened I did get sick and stayed that way for about 2 weeks. I'm very worried about this, I'm only 15 so I don't feel comfortable talking to anyone about this unless it's anonymously. So, is it possible that I could be pregnant? Please help asap. Thank you